hash not being called when using instance as key

Question

I have searched SO and found numerous questions about this very topic, and I've tried recreating accepted answers, but I am unable to duplicate the output shown.

>>> class testFoo(object):
...     def __init__(self,x):
...         self.x = x
...     def __eq__(self, other):
...         return hash(self.x) == other
...     def __hash__(self):
...         return hash(self.x)
...
>>> d = {}
>>> x = testFoo("a")
>>> d[x] = 1
>>> d
{<__main__.testFoo object at 0x7f6d9ccc5550>: 1}
>>> hash(x)
12416037344
>>> hash("a")
12416037344
>>>

What I expected to see when I typed "d" above is a key "a", not the repr string for the object. What am I doing wrong?

adarsh · Accepted Answer · 2016-02-18 01:12:41Z

1

That is because the key is the object and you haven't overriden the default __repr__.

You would need to add this to testFoo class.

def __repr__(self):
    return self.x

answered Feb 18, 2016 at 1:12

adarsh

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1 Comment

cloudtoad Over a year ago

doh! Thanks! Put in there, and it works as expected.

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